The code-hero is a character developed and examined throughout a number of Hemingway's works. Hemingway's code heroes are modern heroes. Their heroism emerges out of their awareness and confrontation of the ultimate nothingness of life and death, nada.
Whereas traditional heroes might be measured solely by prowess in battle (enemies killed, medals acquired), code heroes understand that life itself is a battle and that the trappings of heroism are often empty. Still, code heroes tend to be skilled in fighting and sport.
"In Another Country" is typically read as a code hero story. The narrator learns about the code through his conversations and experiences with the major. The major did not "believe in bravery." In other words, the major did not believe in bravado. True courage happened quietly as the heroes faced nada. Code heroes do feel fear and their journey is marked by their struggles against it.
The major must face the terrible emptiness of his wife's death...an improbable death given her youth. Yet, through his code heroes, Hemingway frequently reminds us that nothing is guaranteed. A code hero must find meaning within himself. "He should find things he cannot lose," the major explains bitterly. But for Hemingway, all things, except one's own code, can be lost. This is what the narrator learns from the major.
Although the major has some of the characteristics of the traditional hero (he fought in a war, he is skilled in fencing, he is intelligent), this is not the heart of the story.